Device in drills



H. H. AHLGREN ETA'. 3,441,097. l

DEVICE IN DRILLS Filed NOV. 29, 1966 TT RNE /S April 29, 1969 United States Patent O U.S. Cl. 175-214 3 Claims ABSTRACT F THE DISCLOSURE There is disclosed drilling apparatus including a drill rod having a `drill head secured on its lower end and having a boring diameter mlaterially greater than the diameter of the rod, a distance sleeve secured at the upper end of the rod and having a depending cylindrical portion, a sleeve member receiving the depending portion and means sealing the depending portion in the sleeve, a generally cylindriform pipe neck having la pipe socket extension providing a ilushing medium inlet and an outwardly extending ilange freely projecting into an annular clearance space in a connecting ilange ring secured on the lower end of the sleeve member, and a tube surrounding and outwardly spaced from the rod and having an outer diameter less than the boring diameter of the drill head and tted over a generally cylindrical portion of the drill head and a portion of the pipe neck and free for limiteld longitudinal and rotational movement relative to said pipe neck and drill head whereby drill head impact and torsional faction take place through the rod only and not through any direct connection between the tube and rod.

The present invention relates to a device in drills for drilling in earth or rocks, wherein the shaft or rod of the drill, winch is provided with a drill head, is surrounded by a tube, the outer diameter of which is at least slightly less than the effective diameter of the ldrilling head.

The known ydevices of this type @are complicated, heavy and costly. They are further affected 'with the disadvantage that the tube is by no means or only with great diiculties capable of being :withdrawn from the bore; this applies at least in all those cases where it is desired to leave the drilling head or crown and the drilling nod in the bore.

The present invention, the object of which is to eliminate these disadvantages, is characterized substantially in that the tube, the rear or outer end of which has an inlet for a flush medium and the front or inner end of which, i.e. the end adjacent the drill head, has one or more inlets for the llush medium, is not attached to or operatively connected to either the drill rod or the drill head but adapted to accompany more or less passively in the sinking or general progressive movement of the drill, any impact or torsional action on the drilling head being performed through the `drilling rod in a manner known per se and not through the tube.

The free mounting of the tube implies also that it may have thin walls and be light and thereby saving material and easy to handle.

The principle of pressing a Hush medium into the space between the drilling rod and the tube surrounding the latter involves thlat no flush passage whatever is required in the boring road and accordingly it will be possible to utilize boring rods without llush passage. These rods cost hardly half of the cost for boring rods provided with a flush passage. This means an extremely important cost saving.

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The invention will be further explained with reference to the drawing.

FIGURE l shows partly in section an embodiment of a drill according to the invention.

FIGURE 2 shows an alternative embodiment of the drill head of the drill rod in question.

1 designates two boring rods interconnected by a connecting sleeve 2, the lower rod being at its lower end rmly connected to a boring head or crown 3. The rods 1 have no interior flush passages, being surnounded b-y two tube members 4 conducting a ush medium and interconnected by a connecting member 5.

On the upper rod 1 a distance sleeve 7 is tted tightly and attached by a securing pin 6 passed through receiving openings in the rod 1 and sleeve 7. A sleeve member 9 provided with a pipe socket `10 forming an inlet 'for a flush medium is sealed to the distance sleeve by means of a sealing ring 8. At its lower end the sleeve 9 is tightly connected to a pipe neck 11 having a lower cylindrical portion 12 received in the upper end of the upper tube 4. A ange 13 of the neck 11 determines the relative position of the tube 4 and the neck 11, in combination with the il-anged ring secured in any approved manner, as by threading or otherwise, to the lower end of the sleeve member `9.

Owing to the sealing relation between the members 7, 8, 9, 11, 12 and 4 a flush medium introduced or pressed through the pipe socket 10 will be forced to move downwards between rod l1 and tube 4. In FIG. 1 the outlet of the tube 1 consists of exterior passages 15 recessed in a cylindrical portion 14 received in the lower end of tube 1, which passages conduct the llush medium to the striking portion of the drilling heard or crown 3. Here the ilush medium receives the loose-worked material or so-oalled bore chippings and carries this up to the ground surface. The path of the flush medium through `all the drilling device is illustrated in FIG. 1 by arrows.

The impact-drilling portion of the drill head 3 may be of any arbitrary design kno-wn per se, preferably provided with cutting inserts of sintered hard metal or the like.

In the embodiment shown in FIG. 1 the passages 15 conduct the ush medium to an annular groove 16 disposed adjacent the effective portion 3 of the head 3.

The drill rods 1 do not need to have any internal rinsing or llushing passages. However, since the passage between the rods and the tubes -along which the liush medium is conducted has a considerable cross-sectional area, a much more ecient ushing action is obtained than what is possible with ordinary boring or ldrill rods provided with internal flush passages or holes. The effective outer diameter of the drill crown 3` should of course be greater than the outer diameter of the tube 4 in order to provide for a suicient ow cross-area also for the upward ilush water flow surrounding the tube 4.

. According to the invention the tube- Ior tube members 4 are not attached directly to or operatively connected to either the drill rod 1 or the drill head 3, 14 but are adapted to follow more or less passively the sinking movement |of the drill, @all impact and torsional `action on the drill head being accomplished through the drill rod and not through the tube.

Preferably a considerable play is provided with the tube 4 in its longitudinal direction, whereby longitudinal movements of the drilling rod are not appreciably impeded by the tube.

The tube 1 is thus free from direct inuence from the forces acting on the drill rod `and the drill head, and the m'ovements of the latter are accordingly not appreciably impeded by the mass of the tube. Since the tube is not inuenced by any major forces nor is to transmit any forces to either the drill rod or the drill head, the tube 3 may be sized relatively thin-walled and thus materialsaving. Thanks to the free tting of the tube the tube will also be `withdrawn from the biore without diiculty if such is desired without moving the drilling rod from the bore.

In FIG. 2 lan alternative embodiment of the outlet of the tube 4 is shown. In this case the fdrill head is provided with drilled passages |17, extending from the space between drill rod 1 and tube 4 through the drill head to the forward facing portions of the latter, where the passages open in a suitable way. The passages 1'7 are in FIG. 2 shown to the disposed approximately parallel to tube 4 and drill rod 1 and the axis of the drill head, but variations from this rule are possible.

A third embodiment of the outlet of the tube 4 may consist simply of a sufficient play between the cylindrical portion of the drill head received in the lower eind of tube 4 and the inner wall of tube 4. Such a play may be combined with the passages 15 and/'or 17 or passages or bores provided in another way.

It will be understood that the invention is not limited to only the embodiments described above and shown on the drawing, since many other embodiments are possible within the scope of the invention.

Thus, the diameter difference between the diameter of the drill rod 1 and the inner diameter of the tube 4 may be substantially less than that indicated in the drawing.

The drill head may be removable by impact in case the tube 4 shall remain in the drilled bore, which occurs in so-called grouting. A removable embodiment of the drill head makes withdrawal of the drilling rods 1 out of the bore after finished drilling and leaving of the tube 4 in the bore hole possible. The withdrawal of the drilling rods is then facilitated by the free mounting of the tube.

Although the invention has been described above as applied in a boring arrangement wherein the drill rod and head are submitted to impact as well as rotational actions from any drilling machinery, the invention may be used also in arrangements with rotational action only.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following claims:

1. In a drilling apparatus, the combination of a drill rod having a drill head secured on its lower end and having a boring diameter materially greater than the diameter of the rod, a distance sleeve secured at the upper end of the rod and having a depending cylindrical portion, a sleeve member receiving said depending portion and means Sealing said depending portion in the sleeve, a generally cylindriform pipe neck having a pipe socket extension providing a liushing medium inlet and an outwardly extending flange freely projecting into an annular clearance space in a connecting flange ring secured on the Ilower end of the sleeve member, and a tube surrounding and outwardly spaced from the rod and having an outer diameter less than the boring diameter of the drill head and an inner diameter communicating with said pipe socket extension through said pipe neck and fitted over a generally cylindrical portion of the drill head and a portion of the pipe neck and free for limited longitudinal and rotational movement relative to said pipe neck and drill head whereby drill head impact and torsional action take place through the rod only and not through any direct connection between the tube and rod.

2. Drilling apparatus as defined in claim 1 wherein said generally cylindrical portion of the drill head is provided with outer surface clearances providing flow passage between its exterior and the interior of the tube to communicate exteriorly of the tube through the bottom thereof.

3. Drilling apparatus as deiined in claim 1 wherein said generally cylindrical portion of the drill head has flow passages extending therethrough and through other portions of the drill head to communicate exteriorly of the tube through the bottom thereof.

References Cited UNITED STATES PATENTS 1,796,457 3/1931 Hansen 175-207 1,816,324 7/1931 Hansen 175-207 FOREIGN PATENTS 256,474 8/ 1926 Great Britain.

CHARLES E. OCONNELL, Primary Examiner.

RICHARD E. FAVREAU, Assistant Examiner. 

